Because agencies use different terminology, their inventories have limited value, GAO finds.

One of the Holy Grails of performance-based government has been assembling a reliable list of all federal programs to help Congress spot duplication and overlap.

But that longtime quest is being thwarted because of inconsistencies in how agencies define programs, making it impossible to compare information, according to a Government Accountability Office report released Friday.

To demonstrate the problem, GAO attempted to locate in relevant agencies' inventories the various science, technology, engineering and mathematics education and nuclear nonproliferation programs the watchdog had previously identified, but it could not find a large majority of the programs in those inventories. “[Nine] of the 179 programs matched exactly and 51 others were identified based on program descriptions,” analysts wrote.

Under the 2010 Government Performance and Results Modernization Act, the Office of Management and Budget is tasked with providing guidance to agencies so that they may compile program lists along with relevant budget data. But in developing the inventory, “OMB allowed for significant discretion in several areas—leading to a variety of approaches for defining programs and inconsistencies in the type of information reported. The inconsistent definitions, along with agencies not following an expected consultation process, led to challenges in identifying similar programs in different agencies. As a result of these limitations, the inventory is not a useful tool for decision making,” the watchdog wrote.

OMB issued updated guidance in May 2013, which prompted GAO’s report to lawmakers.

Sen. Tom Coburn, R-Okla., the retiring ranking member of the Senate Homeland Security and Governmental Affairs Committee, has long criticized the Obama administration taking so long to produce the inventory—making an exception for the Education Department, whose listings Coburn lauds.

GAO, which itself is pressing for the inventory to aid its staff in preparing regular reports on program duplication, also notes that passage of the 2014 Digital Accountability and Transparency Act has altered OMB’s methodology in requiring more program and budget data displayed on federal websites. Further complications could arise if Congress enacts the pending Taxpayers Right-to-Know Act, which would require linking between sites.

To improve the process, GAO recommended that OMB present program-level budget information; provide complete performance information; consult more with stakeholders such as Congress, state and local governments and third-party service providers; and broaden the number of agencies participating from the current 24.

OMB staff generally agreed with the recommendations, though they said they need more time to determine the feasibility of some steps as agencies implement the DATA Act.